WDPN31 PGTW 120300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 29W (PAKHAR) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.1N 129.6E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 397 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS PERSISTENT
DEEP CONVECTION WITH A STRONG CORE WRAPPING AROUND A LOW-LEVEL
CIRCULATION CENTER (LLCC), WHICH IS COMPLETELY OBSCURED BY A
CENTRAL DENSE COVER. TROPICAL STORM PAKHAR IS STILL INTENSIFYING
WITH COLD CLOUD TOP TEMPERATURES REMAINING AROUND THE -70C RANGE,
WITH YET ANOTHER BURST OF OVERSHOOTING TOPS REACHING -89C. A
WELL-TIMED BULLSEYE FROM A 120037Z METOP-B ASCAT IMAGE LENDS HIGH
CONFIDENCE IN THE INITIAL PLACEMENT. THE INITIAL INTENSITY IS
ASSESSED WITH HIGH CONFIDENCE AND REMAINS HEDGED SLIGHTLY HIGHER
THAN MULTIPLE AGENCIES FIXES LISTED BELOW AND THE ASCAT IMAGE. TS
PAKHAR AT THE CURRENT ANALYSIS IS A HIGHLY SYMMETRICAL SYSTEM AND
IS ONLY SLIGHTLY IMPACTED BY THE UNFAVORABLE REGION OF STRONG
(25-30KTS) VERTICAL WIND SHEAR (VWS) TO THE NORTH. STRONG POLEWARD
OUTFLOW IS NOW THE MAIN VENTILATION FOR TS 29W, AND THE SEA SURFACE
TEMPERATURES REMAIN WARM (28C-29C).

INITIAL WIND RADII BASIS: SCATTEROMETER DATA FROM A 120037 METOP-B
IMAGE.

CURRENT STEERING MECHANISM: NORTHWEST PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED WELL TO THE EAST-NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 57 KTS AT 112340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 30+ KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TS 29W WILL TRACK TO THE NORTHEAST AS IT
REMAINS UNDER THE STEERING INFLUENCE OF THE STR TO THE
EAST-NORTHEAST OVER THE NEXT 12 HOURS. THEREAFTER, THE UPPER-LEVEL
CIRCULATION WILL BEGIN TO DECOUPLE FROM THE LOWER CIRCULATION DUE
TO THE STRONG VWS, WHICH WILL CONTINUE TO COMBAT THE LLCC. AT OR
NEAR TAU 24, TS PAKHAR LLCC IS EXPECTED TO TURN TOWARD THE
SOUTHEAST AND THEN SOUTH-SOUTHWEST THROUGH THE REMAINING FORECAST
PERIOD ONCE IT FULLY DECOUPLES THE UPPER-LEVEL FROM THE LOWER-LEVEL
CIRCULATION. BY TAU 36, THE LLCC WILL ALSO BEGIN ENCOUNTERING AN
INFLUX OF STRONGER LOW AND MID-LEVEL DRY AIR, WHICH WILL ENGULF THE
MOISTURE AS THE SYSTEM COMPLETELY DISSIPATES OVER THE EASTERN
PHILIPPINE SEA BY TAU 48 IF NOT SOONER. 

MODEL DISCUSSION: MOST OF THE NUMERICAL MODEL GUIDANCE REMAINS
CONVINCED ON THE OVERALL TRACK MAKING THE SOUTHEAST TURN WITHIN THE
NEXT 12 TO 24 HOURS. THE EXACT TIMING AND SHARPNESS OF THE TURN
CONTINUE TO VARY GREATLY FROM RUN TO RUN BETWEEN EACH OF THE MODEL
SOLUTIONS. THE SHARPEST TURNING MODELS ARE FROM THE GFS AND ITS
ENSEMBLE SOLUTION, WHICH MAKE A COMPLETE U-TURN SOUTHWEST SHORTLY
AFTER TAU 12. THE REMAINING MODELS DO NOT FORECAST THE SYSTEM
TURNING NEAR AS SHARP AND TURN IT SOUTHEAST JUST AFTER TAU 24. THE
INCONSISTENCIES BETWEEN EACH OF THE MODEL RUNS LEND ONLY LOW
CONFIDENCE IN THE OVERALL JTWC TRACK. INTENSITY GUIDANCE REMAINS
MIXED, WITH THE PEAK INTENSITY REMAINING AT 50 KNOTS, DECREASING
FROM TAU 12 UNTIL THE END OF THE FORECAST PERIOD BY TAU 48, LENDING
ONLY MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM//
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